Question: $\overline{AC}$ is $9$ units long $\overline{BC}$ is $10$ units long $\overline{AB}$ is $\sqrt{181}$ units long What is $\cos(\angle ABC)$ ? $A$ $C$ $B$ $9$ $10$ $\sqrt{181}$
Solution: SOH CAH TOA os = djacent over ypotenuse adjacent $= \overline{BC} = 10$ hypotenuse $= \overline{AB} = \sqrt{181}$ $\cos(\angle ABC )=\frac{10}{\sqrt{181}}$ $=\dfrac{10\sqrt{181} }{181}$